In recent years, there has been extraordinary expansion in the ownership and utilization of computers. Computers, once considered primarily the tools of scientists, can now be found in a substantial portion of homes and businesses. Though partial credit for the unprecedented growth in the utilization of computers is attributable to lower costs associated with manufacturing computers and related peripheral devices which has made such equipment affordable to a much larger segment of the public, the credit is equally, if not more, attributable to the enhanced versatility, ease in learning to use, and ease of using computers as a result of the improved operating systems and applications software running on the computers.
It is therefore very important when designing an operating system or application program, and more particularly a user interface for such software, to provide a high degree of user friendliness, which incorporates ease of learning and ease in using the operating system or application program. Users appreciate operating system and application program interfaces which enable them to accomplish their computer related tasks intuitively and without the need to master obscure and complicated commands or routines. A considerable portion of the computer users today base their preference for a particular operating system or application program upon such software's ease of use which consequently results in a savings of time and effort for the user, as well as display features provided by the operating system or application program software which enhance the aesthetic appeal of the interface.
The Windows.RTM. .sup.Microsoft Corporation operating system and its series of menus and buttons has significantly simplified using the personal computer. The Windows.RTM. .sup.Microsoft Corporation operating system is unquestionably easier to learn than earlier text command based operating systems. Even more importantly, the Windows.RTM. .sup.Microsoft Corporation operating system enables a user to access a great number and variety of computer resources from any given screen by selecting from the title bars, menu items, and control buttons provided by the graphic user interface. As used herein, the term computer resource is intended to encompass a wide variety of data and functions provided by a computer including for example files, directories, programs, commands, and controls.
It is of course desirable for an operating system or application program to provide access to a large quantity of computer resources via a single display screen. However, increasing the computer resources accessible via the single display screen requires providing additional graphical user interface targets such as menu items, command bars, and/or control buttons which, in turn, increases cluttering of the display screen. Cluttering degrades both the ease of use and the aesthetic appeal of a graphical user interface. Therefore, one consideration when developing a user interface for an operating system or application program is to provide the user with access to a large quantity of computer resources via a single display screen while avoiding filling the limited available space of the display screen of the graphical user interface with target images associated with the computer resources. Of course the difficulty in meeting these seemingly contradictory objectives is enhanced in new hand-held or reduced size computers having smaller display screens.
One way to avoid consuming the limited area of a display screen with target images without reducing the number of computer resources presented on a single display screen is to reduce the size of the graphical user interface target images and their associated detection regions. However, reducing the size of the detection regions for the graphical user interface target images reduces the margin for error when positioning the pointer and increases the level of precision needed to position a mouse controlled display pointer for selecting a computer resource associated with a target image. As a result, users may experience an increased difficulty in positioning a pointer within a detection region and selecting a computer resource associated with the target image displayed within the detection region. This problem is most evident in computers having smaller size display screens.
A known alternative to reducing the size of the target images displayed upon a graphical user interface is to replace a set of related target images by a representative target image which consumes considerably less display screen space than the target images. When a user selects the representative target image by moving a mouse-controlled pointer within the detection region associated with the representative target image and clicking (i.e., pressing down and releasing) a mouse button, the set of related target images are displayed upon the display screen. Thus, graphic user interfaces incorporating the above target image "hiding" feature conserve the limited display screen space by displaying a set of targets only after a user points to and clicks upon an associated target image.
Known graphical user interfaces for operating systems and applications programs have incorporated the above described "hiding" feature into menu bars. These known menu bars display a set of menu headings. After a user moves the pointer within the boundaries of the detection region for one of the menu headings and then clicks a mouse button, the graphical user interface displays a set of target images below the menu heading representing computer resources. The set of target images are removed from the display when a user clicks a mouse button.
Also, a known command bar provides space saving characteristics. When not selected, the command bar is represented on the graphical user interface by an icon which, when selected using the pointing to the icon and clicking a mouse button, is replaced by a full-size command bar. The full-size command bar is replaced by the icon when a user clicks a mouse button or moves the pointer outside the detection region associated with the full-size command bar.
The above-described known graphical user interface features promote conservation of screen space and reduce clutter while providing access to a large quantity of computer resources. However, the manner in which the "hidden" computer resources are presently accessed, namely pointing and clicking on a small icon, presents certain drawbacks. The user may click the mouse while the pointer is not within the detection region of the intended item. Even when the pointer is originally positioned by a user within the boundaries of a detection region, the user may inadvertently move the pointer to a position outside the boundary while clicking the mouse button. Such occurrences are not uncommon when the graphical user interface provides small detection regions and/or when the user is in a hurry. Furthermore, though clicking a mouse button seems to be a relatively simple task, having to repeat the act one or more times due to a previous erroneous positioning of the pointer while clicking the mouse button can be annoying to a user.
Another concern of computer interface developers is the ease with which the users learn to use a new interface feature. One of the advantages provided by graphical user interfaces for operating systems and application programs is the ease with which users learn to invoke the various controls and commands provided by such software--often without formal training or consulting an instruction manual. Much of the success in improving the ease with which users learn to use the operating systems or application programs is attributed to the large amount of information provided at each decision making step. Removing some of this information from constant view adversely affects the user's ability to discover and utilize the hidden features without resorting to formal instruction. Therefore, when certain information is removed from a screen in order to reduce clutter, it is important from the user's standpoint that such retracted graphic user interface features remain easily discoverable without having to resort to an instruction manual.